Dual-emitting BP-CdTe QDs coupled with dual-function moderator TiO NSs for electrochemiluminescence ratio bioassay.

The limitation of the selection of dual-emitting luminophor and dual-function moderator makes the construction of single-luminophor-based electrochemiluminescence (ECL) ratio strategy extremely challenging. This work developed black phosphorus nanosheet loaded with CdTe quantum dots (BP-CdTe QDs) as dual-emitting luminophor, and TiO nanosheets (NSs) as dual-function moderator to construct single-luminophor-based ECL ratio biosensor for amyloid-β protein (Aβ) detection. The BP-CdTe QDs modified glassy carbon electrode (GCE) firstly captured the anti-Aβ, and then the target Aβ. Finally, the secondary antibody composites containing N,N-diethylethylenediamine (DEDA) and TiO NSs were captured on the electrode surface. DEDA in the secondary antibody composites and SO added in the detection solution served as the anodic and cathodic co-reactants, respectively, and TiO NSs as co-reaction accelerator can simultaneously enhance two emissions. The increase of target concentration made the two signals show different increasing trend, thus achieving a sensitive ratio detection of target Aβ with the detection limit of 21 fg/mL. The dual-emitting BP-CdTe QDs coupled with dual-function moderator TiO NSs provide an attractive single-luminophor-based ECL ratio platform for bioassay, which can not only be applied to the detection of Aβ, but also to the detection of other disease biomarkers.